The invention relates to a firing direction system for a rocket launcher, especially a firing direction system for the adjustment of the rockets during the launching toward a prescribed target.
The functional elements of a conventional firing direction system are illustrated in FIG. 1. The output shaft 10 of a motor 9 drives the input shaft 8 of a safety brake mechanism that automatically closes under load. In the rocket launchers used in the military, the motor is a hydraulic motor. The rocket launcher, which is installed on a vehicle, will be designated in the following as a load. The output shaft 10 of the safety brake mechanism is connected with the load. The load itself is not illustrated in this description.
The function of the safety brake mechanism is to reliably hold the greatly imbalanced, i.e. downwardly driving, load even if the blocking brake on the motor fails or is incorrectly controlled (the blocking brake on the motor is not illustrated in FIG. 1) or if the drive motor fails or functions incorrectly, and to protect against an uncontrolled falling down of the load. Furthermore, during the lowering of the imbalanced load, the brake converts the potential energy into heat, which would otherwise heat up the oil.
An improved hydraulic type of drive is also known for the same use, whereby during the lowering of the load, the oil is conveyed into a pressure tank in order to store the potential energy. In this connection, the counter pressure of this storage means is also used in order to brake or retard the falling-down load when the motor control fails or if there is an incorrect functioning of the motor. Although these drives operate without a safety brake, they maintain the drawback of hydraulics. Hydraulic oil must be removed, the drive efficiency is low, the development of noise is high, and oil is combustible.
Also known is the use of regulated, brushless electric motors for the drive of a rocket launcher. In this connection, however, a brake must be externally controlled in order to achieve the braking effect during stand still, when an incorrect functioning occurs, or upon failure of the motor. This design has not yet been proven with regard to functional reliability, and has not yet been introduced with troops.
The functioning of this safety brake mechanism will be described in detail in the following for the individual operating conditions with the aid of FIG. 1. The invention can, however, also be used with other safety brake mechanisms.
1. Functional description for the state of rest, i.e. the rocket launcher (the load) is to be held in a desired position:
The output shaft 1 of the brake mechanism engages via teeth with an inner plate carrier 2 of a multiple-plate brake. The output shaft 1 and the inner plate carrier 2 can be displaced axially relative to one another; however, in the radial direction the two shafts 1 and 2 are interconnected.
The multiple-plate brake 3, by means of the bias of a torsion spring 4, which rotates the two shafts 2 and 8, is closed by the action of the inclined surfaces 5 and 5′. The outer plate carrier 6 is supported on a return stop 7 that permits no rotation in the direction—load downward. The brake is thereby effective, and the rocket launcher is held in its position.
2. Functional description for the function—motor drives the load upwardly (raising):
The drive shaft 8 is driven by the motor against the effect of the load. The multiple-plate brake is pressed further together by the inclined surfaces 5 and 5′ and remains closed as long as the load is directed downwardly. The outer plates of the multiple-plate brake are supported in a plate carrier 6 against rotation. This plate carrier 6 is, in turn, connected with a free-running drive 7. This free-running drive 7 is freely rotatable in the direction—load upwardly. The brake mechanism can thus rotate with the motor in an unobstructed manner and can raise the load.
3. Functional description for the function—motor drives the load downwardly (lowering):
The drive shaft 8, against the bias of the torsion spring 4, rotates the closed brake open to such an extent until the inclined surfaces 5 and 5′ release the pressure upon the plates of the brake, and the torque of the brake is less than the torque of the downwardly driving load.
The output shaft 1 can, in this connection, rotate only as rapidly as the shaft 8 is driven. As soon as the load tries to overtake the shaft 8, the brake is closed by the inclined surfaces 5 and 5′.
The reliable support of the load achieved with this mechanism could also be achieved with an automatically arresting gear mechanism that is built into the drive string, or with an automatically arresting spindle or worm. The advantage of the above-described safety brake of the state of the art, relative to such an automatically arresting gear mechanism, is, however, that the described mechanism operates with a considerably better efficiency during the raising of the load than would be the case, for example, with an automatically arresting worm or screw drive.
An important drawback of the above-described embodiment with the safety brake, as well as with every automatically arresting gear mechanism, is, however, that during the lowering of the load, the potential energy that is in the load is completely converted into frictional energy. In this connection, the brake becomes worn and heats up. The wear limits the number of operations of the firing direction system and hence the service life of the brake. The heating of the system also limits the number of successive downward directing processes. Furthermore, the braking effect per unit of time of each frictional brake is limited, as a result of which the speed during the lowering of the load is limited.
In addition, especially with firing direction systems for weapons, it is very important that the directing processes can be carried out with as little development of noise as possible.
It is an object of the present invention to provide a firing direction system for a rocket launcher that avoids the aforementioned drawbacks.